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A225348 Number of 8Xn -1,1 arrays such that the sum over i=1..8,j=1..n of i*x(i,j) is zero, the sum of x(i,j) is zero, and rows are nondecreasing (number of ways to distribute n-across galley oarsmen left-right at 8 fore-aft positions so that there are no turning moments on the ship) 1
8, 77, 410, 1525, 4508, 11291, 25056, 50659, 95130, 168289, 283338, 457627, 713374, 1078615, 1587974, 2283803, 3217102, 4448769, 6050622, 8106883, 10715232, 13988475, 18055740, 23064277, 29180742, 36593245, 45512628, 56174753, 68841880 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 8 of A225345

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = a(n-1) +a(n-2) -a(n-5) -a(n-7) -a(n-8) +a(n-10) +a(n-11) +2*a(n-12) -2*a(n-16) -a(n-17) -a(n-18) +a(n-20) +a(n-21) +a(n-23) -a(n-26) -a(n-27) +a(n-28)

EXAMPLE

Some solutions for n=4

.-1..1..1..1...-1..1..1..1...-1..1..1..1...-1..1..1..1...-1.-1..1..1

.-1..1..1..1...-1..1..1..1...-1.-1.-1.-1...-1.-1..1..1...-1.-1.-1..1

.-1.-1..1..1...-1.-1..1..1...-1..1..1..1...-1..1..1..1...-1..1..1..1

.-1.-1.-1.-1...-1.-1.-1.-1...-1.-1.-1..1...-1.-1.-1.-1...-1.-1.-1..1

.-1.-1.-1.-1...-1.-1.-1..1...-1.-1..1..1...-1.-1.-1..1....1..1..1..1

.-1..1..1..1...-1.-1.-1..1...-1..1..1..1...-1.-1..1..1...-1.-1..1..1

.-1.-1.-1..1...-1.-1..1..1....1..1..1..1...-1.-1.-1..1...-1.-1.-1..1

..1..1..1..1....1..1..1..1...-1.-1.-1.-1....1..1..1..1...-1.-1..1..1

CROSSREFS

Sequence in context: A024281 A232087 A105429 * A091686 A091691 A024103

Adjacent sequences:  A225345 A225346 A225347 * A225349 A225350 A225351

KEYWORD

nonn

AUTHOR

R. H. Hardin May 05 2013

STATUS

approved

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Last modified October 23 11:46 EDT 2021. Contains 348212 sequences. (Running on oeis4.)